Lost Sheep: I am beginning to understand that one can shoot better with a longer gun,...but also something I could use on a monthly basis.

You are welcome. And thanks for the individual reply.

Since you have decided against the shotgun, I will give you my considered recommendation for a handgun house gun.

Since you are interested in shooting for fun as well as for defense, something with good target sights and the ability to group well. It is nothing but frustrating to shoot with a gun that does not shoot as well as you do. ALL of my guns shoot better than I do. That means, as I practice, I can see improvement. Seeing improvement is edifying. Not seeing improvement is discouraging.

Many of the service pistols are not accurate enough to meet that requirement.

The .357 cartridge can be a bit overkill, but many full-size and medium frame guns are accurate and good, Muzzle blast and flash can be problematic in one's own home, not to mention overpenetration.

A .44 Special, .45 Colt or .45 ACP is good, though the ammunition is a bit more expensive than 38 Special or .357 Magnum.

Here's my recommendation:

Get a .22 rimfire and matching centerfire that handle similarly (e.g. Ruger's 22/45 and any decent 1911, which are available in 9m, .40 S&W and 45 ACP, by the way) The rimfire is cheap to practice with and develops handgun skills (especially sight alignment, which is different than with a rifle).

Having a rimfire handgun first will also put you on the handgun range and allow you to see many other guns being used. Might even get to shoot a few. You know how proud most gun owners are of their hardware and like to have other shooters admire them.

I would tend to be partial to a used 5.5" Ruger Redhawk in 44 Magnum, loaded with 44 Special ammunition for home use.

My current bedside gun is a 6" Ruger Security Six loaded with frangible ammunition to reduce the danger to anyone outside my exterior walls.

I occasionally substitute a Taurus Millenium 45 ACP that, remarkably, groups as well as my Colt Gold Cup, despite the rudimentary sights, short barrel and Taurus reputation. It has a rail for laser sight/flashlight to be attached.

Revolvers have their springs "at rest" all the time, which some people see as an advantage. They are simple to operate and very reliable. If you wake from a deep sleep and need to respond to an emergency, operating a revolver is dead simple and there is (with a double action revolver) a long trigger pull to make accidental discharges less likely.

With lots of practice, the semi-auto does hold something of an edge in a firefight (in my opinion).

So, recommendation: A target 22rimfire first. Then for centerfire; Target sights. Ability to group well. Minimum caliber .357 diameter, and the larger the better. In your price range a used revolver in good condition, say, a Ruger GP100 38/357 or Ruger Redhawk 44. Any accurate 1911 (Remington 1911 or Ruger 1911 are running around $700 new, in stainless steel). I have a Taurus 99 in 9mm that is very nice, but I like bigger bullets than that. The DA/SA aspect makes the first shot deliberate and followup shots are single action.

Note: you can load your own ammunition and cut your ammo costs greatly with an investment in a good loading setup. Take the cost of 10 boxes of ammo and you can load up 10 boxes worth for the same money. After that the savings just mount up.